Packing for slide-valves.



E. H. TARTRAIS. PACKING FOR SLIDE VALVES.

' APPLIOATION FILED 11119.22, 1911.

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PACKING FOR SLIDE-VALVES.

To all 'wh-0m, t may concern Be it known that I, EUGNE HENRI TAR-'rRxis, a citizen of the French Republic, residing at 32 Itue desChesneaux, Montmorency, Seine-et-Oise, France, have invented a certainnew and useful Improvement in Hermetic Packings for the Slide-Valves ofInternal-Combustion Engines, of which the following is a specification,such as will enable others skilled in the art to which it appertains tomake and use the same.

This invention has reference to a packing for the slide valves ofinternal combustion engines occasioning but slight friction andconsequently enabling them to work at high temperatures which. rendersthe lubrication difficult, absorbing but little power in spite of thehigh sliding velocities that can be attained.

According to the invention the packing is formed by a ring pressed by aspring against the surface of the slide valve and arrangedin a pipecommunicating with the cylinder and is provided on this side with anauxiliary packing, preferably formed of an expanding split ring, and inwhich the dimensions of the ring are such that the surface on which thepressure of the gas acts for thrusting it against the slide valve isrelatively small with respect to the friction surface of the ring on theslide valve. Furthermore in order to prevent any counter-pressure beingproduced that would tend to move the ring away from the slidevalve, adeep groove with exhaust channels is formed in the surface of the ringpressing against the slide valve for the purpose of expanding thepractically unavoidable slight escape of gas.

In the drawings z-Figure 1 is a cross section of the slide valve. Fig. 2is a section along the line llt-B of the packing ring. Fig. 3 is a planview of the said ring showing its frictional surface.

1 is the cylinder of the engine or a cylindrical pipe communicating withthis cylinder.

2 is the slide valve which in this case is supposed to be cylindricaland which is moved along or around its axis 3. The ports of this slidevalve are not shown, the distributing phases not being concerned in thepresent invention. In the position shown the cylinder is closed by theslide valve and t-he engine is consequently in the cycle of compressionor in the working cycle.

Speccaton of Letters Patent.

Application led August 22, 1911.

Patented Julyg, 1912.

Serial No. 645,361.

The slide valve by itself would permit of leakage, a cert-ain clearanceexisting at 4, the minimum amount of which is determined by thenecessity of permitting the expansion of the said slide valve. Thepacking is formed by. a ring 5 which engages in the pipe 1 with slightclearance at 6 and 7, so as to permit of expansions and which on theother hand rests exactly with its surface 8 against the slide valve.lIhe existence of clearance at 6 renders it advisable to employ apacking at this spot. In the drawing for the sake of example anexpanding ring 9 is shown working as a piston packing ring. A spring ofany desired shape, shown in the drawing as an undulated washer 10, restson the body of the cylinder and tends to thrust the packing ring againstthe slide valve.

At 11 a deep groove is formed passing right around the packing ring andcommunicating with the atmosphere, by means of radial grooves 12. Theobject of this arrangement is as follows A slight leakage tends to beproduced between the packing surfaces of the ring 5 and the slide valve2, because practically the packing surfaces can never be sufficientlyperfect to prevent it, the more so as the spring 10 is very weak, thisbeing intentionally the case for the purpose of attenuating anyfriction. However little this leakage may be (considered from thestandpoint of the loss of gas), it nevertheless occasions pressurebetween the contact surfaces of the packing ring and of the slide valve,which if the above-mentioned arrangement of grooves were not provided,would tend to move the ring away from the slide valve, the more so asthe surface of the packing ring is, for the purpose of attenuating theload per unit of supporting surface, intentionally relatively large,with respect to the annular surface limited by the circumferences ofdiameters D and D1 which receives the oppositely directed thrust. 'Ihepresence of the groove 1l is for the purpose of expanding this leakagegas from the inner edge of the said groove, so that the counter-pressureis only occasioned in the portion 13, comprised between the inner edgeof the ring and the inner edge of the deep groove 11. The suitabledimensions of the diameters D, D1 and D2 can be obtained experimentally,and may be such that the packing is practically balanced for certainconditions of gas pressure, of spring power and of adjustability; thislimit need not be attained and by making D2 smallerv than D there willalways exist an excedent pressure tending to thrust the ring 5 againstthe slide valve.

The preceding description is given for the sake of example, but variousmodifications can be introduced without in any way modifying thefundamental principle of the invention. The slide valve instead of beingcylindrical may be of any desired shape such as conical, spherical,plane and the like, the packing ring being correspondingly adapted toit. Furthermore the slide valve may be fixed and the cylinders movable.The grooves 12 may be radial or oblique, or be substituted by any pipefulfilling the purpose prosecuted, that is to say of connecting the deepgroove 11 with the atmosphere. In certain cases the groove 11 need notbe continuous, so as to comply ywith certain requirements of thedistribution. A judicious determination of the surfaces will in thiscase compensate the resulting disadvantage. In certain cases theclearance 4 may be considerably increased and will no longer constitutea clearance, but a large free gap. The same applies to the clearance 7.In certain cases and moreparticularly when employing metals having a lowcoe'liicient of expansion the clearance 6 may be reduced to apractically Zero value and will thus permit of dispensing with theauxiliary packing 9,

That I claim and desire to secure by Letters Patent is l. A packing fo-rvalves of internal combustion engines comprising a pipe communicatingwith the cylinder, a ring having a friction surface disposed in saidpipe, a valve contacting with the friction surface of said ring, aresilient member pressing said ring against the surface of said valve,an annular groove in said ring and vents connecting said groove with theouter air.

2. A packing for valves of internal combustion engines comprising a pipecommunicating with the cylinder, a ring 5 having a friction surfacedisposed in said pipe and having a side groove and a surface groove, avalve contacting with the friction surface of said ring, an undulatingspring pressing said ring against the surface of said valve, anexpanding ring in the side groove of said ring 5, and means to connectthe surface groove of said ring 5 with the outer air.

In witness whereof I have hereunto set my hand in presence of twowitness.

EUGNE HENRr TARTRAIS.

IVitnesses:

CHARLES BLONDEL,

I-I. C. Coxn.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Eatents, Washington, I). C.

